Cytokine expression in allergic inflammation: systematic review of in vivo challenge studies

Establishment of a human nasal epithelium model of histamine-induced inflammation to assess the activity of fexofenadine as an inverse agonist and its link to clinical benefit

Background

Fexofenadine (FEX) is an antihistamine that acts as an inverse agonist against histamine (HIS) receptor 1 (H1R), which mediates the allergic reaction. Inverse agonists may be more potent than neutral antagonists, as they bind the same receptor as the agonist (HIS) but stabilize the inactive form and induce an opposite pharmacological response, suppressing the basal activity of H1R and preventing HIS from binding. This study aims to establish and validate a model of HIS-induced inflammation based on fully reconstituted human nasal epithelial tissue to assess the activity of FEX as an inverse agonist in this model and explore its link to clinical benefit.

Methods

The model was developed using nasal MucilAir™ (Epithelix) in vitro epithelium challenged by HIS. Two conditions were assessed in a side-by-side comparison: tissue was exposed to HIS + FEX with or without FEX pre-treatment (one-hour prior to HIS challenge). Tissue functionality, cytotoxicity, H1R gene expression, and inflammatory cytokines were assessed.

Results

HIS at 100 µM induced significant 3.1-fold and 2.2-fold increases for inflammatory biomarkers interleukin (IL)-8 and IL-6, respectively (p < 0.0001), as well as rapid upregulation of H1R mRNA. Inflammatory biomarkers were inhibited by FEX and H1R expression was significantly reduced (p < 0.0001). FEX alone decreased H1R expression at all doses tested. With one-hour FEX pre-treatment, there was significantly higher downregulation of IL-8 (p < 0.05) and further downregulation of H1R expression and IL-6 versus without FEX pre-treatment; the effects of FEX were improved from 22% to 40%.

Conclusion

A model of HIS-induced airway inflammation was established based on IL-8, IL-6 and H1R gene expression and was validated with FEX. FEX works as an inverse agonist, with a higher effect when used before+during versus only during the HIS challenge. Taking FEX before+during allergen exposure, or when symptoms first occur, may reduce basal activity and H1R gene expression, providing stronger protection against the worsening of symptoms upon allergen exposure.

Asthma and the Missing Heritability Problem: Necessity for Multiomics Approaches in Determining Accurate Risk Profiles

Asthma is ranked among the most common chronic conditions and has become a significant public health issue due to the recent and rapid increase in its prevalence. Investigations into the underlying genetic factors predict a heritable component for its incidence, estimated between 35% and 90% of causation. Despite the application of large-scale genome-wide association studies (GWAS) and admixture mapping approaches, the proportion of variants identified accounts for less than 15% of the observed heritability of the disease. The discrepancy between the predicted heritable component of disease and the proportion of heritability mapped to the currently identified susceptibility loci has been termed the ‘missing heritability problem.’ Here, we examine recent studies involving both the analysis of genetically encoded features that contribute to asthma and also the role of non-encoded heritable characteristics, including epigenetic, environmental, and developmental aspects of disease. The importance of vertical maternal microbiome transfer and the influence of maternal immune factors on fetal conditioning in the inheritance of disease are also discussed. In order to highlight the broad array of biological inputs that contribute to the sum of heritable risk factors associated with allergic disease incidence that, together, contribute to the induction of a pro-atopic state. Currently, there is a need to develop in-depth models of asthma risk factors to overcome the limitations encountered in the interpretation of GWAS results in isolation, which have resulted in the missing heritability problem. Hence, multiomics analyses need to be established considering genetic, epigenetic, and functional data to create a true systems biology-based approach for analyzing the regulatory pathways that underlie the inheritance of asthma and to develop accurate risk profiles for disease.

Association of Maternal Immune Activation during Pregnancy and Neurologic Outcomes in Offspring

OBJECTIVE

To evaluate neurologic morbidity among offspring during their first year of life in association with prenatal maternal immune activation (MIA), using an inclusive definition.

STUDY DESIGN

This retrospective cohort study included singletons born in California between 2011 and 2017. MIA was defined by International Classification of Diseases diagnosis of infection, autoimmune disorder, allergy, asthma, atherosclerosis, or malignancy during pregnancy. Neurologic morbidity in infants was defined by International Classification of Diseases diagnosis of intraventricular hemorrhage, periventricular leukomalacia, seizures, abnormal neurologic examination, or abnormal neurologic imaging. Outcomes of delayed developmental milestones during the first year of life were also explored. Risk of neurologic morbidity in offspring was approximated for women with and without MIA using log link binary regression.

RESULTS

Demographic characteristics among 3 004 166 mother-infant dyads with or without MIA were similar in both groups. Rate of preterm delivery in mothers with MIA (9.4%) was significantly higher than those without MIA (5.6%). Infants of mothers with MIA were more likely to experience neurologic morbidities across all gestational ages. Adjusted relative risk (95% CI) in the exposed infants was 2.0 (1.9-2.1) for abnormal neurologic examination; 1.6 (1.5-1.7) for seizures, and 1.6 (1.4-1.8) for periventricular leukomalacia.

CONCLUSIONS

Our results demonstrate that MIA during pregnancy may be associated with considerably higher risk of neurologic morbidity in offspring.

Increased IL-6 and Potential IL-6 trans-signalling in the airways after an allergen challenge

BACKGROUND

In asthma, IL-6 is a potential cause of enhanced inflammation, tissue damage and airway dysfunction. IL-6 signalling is regulated by its receptor, which is composed of two proteins, IL-6R and GP130. In addition to their membrane form, these two proteins may be found as extracellular soluble forms. The interaction of IL-6 with soluble IL-6R (sIL-6R) can trigger IL-6 trans-signalling in cells lacking IL-6R. Conversely, the soluble form of GP130 (sGP130) competes with its membrane form to inhibit IL-6 trans-signalling.

OBJECTIVES

We aimed to analyse IL-6 trans-signalling proteins in the airways of subjects after an allergen challenge.

METHODS

We used a model of segmental bronchoprovocation with an allergen (SBP-Ag) in human subjects with allergy. Before and 48 h after SBP-Ag, bronchoalveolar lavages (BALs) allowed for the analysis of proteins in BAL fluids (BALFs) by ELISA, and membrane proteins on the surface of BAL cells by flow cytometry. In addition, we performed RNA sequencing (RNA-seq) and used proteomic data to further inform on the expression of the IL-6R subunits by eosinophils, bronchial epithelial cells and lung fibroblasts. Finally, we measured the effect of IL-6 trans-signalling on bronchial fibroblasts, in vitro.

RESULTS

IL-6, sIL-6R, sGP130 and the molar ratio of sIL-6R/sGP130 increased in the airways after SBP-Ag, suggesting the potential for enhanced IL-6 trans-signalling activity. BAL lymphocytes, monocytes and eosinophils displayed IL-6R on their surface and were all possible providers of sIL-6R, whereas GP130 was highly expressed in bronchial epithelial cells and lung fibroblasts. Finally, bronchial fibroblasts activated by IL-6 trans-signalling produced enhanced amounts of the chemokine, MCP-1 (CCL2).

CONCLUSION AND CLINICAL RELEVANCE

After a bronchial allergen challenge, we found augmentation of the elements of IL-6 trans-signalling. Allergen-induced IL-6 trans-signalling activity can activate fibroblasts to produce chemokines that can further enhance inflammation and lung dysfunction.

Systems biology and big data in asthma and allergy: recent discoveries and emerging challenges

Asthma is a common condition caused by immune and respiratory dysfunction, and it is often linked to allergy. A systems perspective may prove helpful in unravelling the complexity of asthma and allergy. Our aim is to give an overview of systems biology approaches used in allergy and asthma research. Specifically, we describe recent "omic"-level findings, and examine how these findings have been systematically integrated to generate further insight.Current research suggests that allergy is driven by genetic and epigenetic factors, in concert with environmental factors such as microbiome and diet, leading to early-life disturbance in immunological development and disruption of balance within key immuno-inflammatory pathways. Variation in inherited susceptibility and exposures causes heterogeneity in manifestations of asthma and other allergic diseases. Machine learning approaches are being used to explore this heterogeneity, and to probe the pathophysiological patterns or "endotypes" that correlate with subphenotypes of asthma and allergy. Mathematical models are being built based on genomic, transcriptomic and proteomic data to predict or discriminate disease phenotypes, and to describe the biomolecular networks behind asthma.The use of systems biology in allergy and asthma research is rapidly growing, and has so far yielded fruitful results. However, the scale and multidisciplinary nature of this research means that it is accompanied by new challenges. Ultimately, it is hoped that systems medicine, with its integration of omics data into clinical practice, can pave the way to more precise, personalised and effective management of asthma.

Hsa_circ_0005519 increases IL-13/IL-6 by regulating hsa-let-7a-5p in CD4+ T cells to affect asthma

BACKGROUND

Circular RNAs (circRNAs) are a class of non-coding RNAs that could serve as novel biomarkers for the diagnosis and treatment of diseases. We hypothesized that circRNAs of CD4⁺ T cells are involved in asthma.

OBJECTIVE

In this study, we investigated the circRNA expression profile and the possible mechanism by which hsa_circ_0005519 participates in asthma.

METHODS

The expression profiles of circRNAs in CD4⁺ T cells were revealed by circRNA microarray. Hsa_circ_0005519 expression in CD4⁺ T cells was confirmed in asthmatic patients (n = 65) and healthy subjects (n = 30). Hsa-let-7a-5p, the target of hsa_circ_0005519, was predicted by online algorithms and verified by a dual-luciferase reporter assay. Correlation assays between the expression of hsa_circ_0005519 and hsa-let-7a-5p, the mRNA levels of interleukin (IL)-13 and IL-6 in CD4⁺ T cells, and the clinical characteristics of asthmatic patients were performed. The role of hsa_circ_0005519 in proinflammatory cytokine expression was investigated in CD4⁺ T cells from asthmatic patients in vitro. Hsa_circ_0005519 expression in PBMCs was determined in another cohort including 30 asthmatic patients and 24 controls. Correlation assays of hsa_circ_0005519 expressions between CD4⁺ T cells and PBMCs were performed.

RESULTS

Hsa_circ_0005519 was up-regulated and negatively correlated with hsa-let-7a-5p expression in CD4⁺ T cells of asthmatic patients. Both the fraction of exhaled nitric oxide (FeNO) and the peripheral blood eosinophil ratio were positively correlated with hsa_circ_0005519 expression in CD4⁺ T cells. These outcomes were also different in asthmatic patients with low vs high hsa_circ_0005519 levels. Hsa_circ_0005519 expressions between CD4⁺ T cells and PBMCs were concordant in asthmatic patients. Mechanistically, hsa_circ_0005519 might bind to hsa-let-7a-5p and relieve suppression for IL-13/IL-6 in CD4⁺ T cells.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data suggest that hsa_circ_0005519 may induce IL-13 and IL-6 expression by regulating hsa-let-7a-5p in CD4⁺ T cells to affect asthma. And hsa_circ_0005519 may be a potential biomarker of asthma.

The Iron Chelator and Anticancer Agent Dp44mT Relieves Allergic Inflammation in Mice With Allergic Rhinitis

Our previous study showed that an iron chelator and anticancer agent Di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT) has an antiinflammatory effect in human mast cells. However, antiinflammatory effect of Dp44mT remains unclear in animal models. In this study, we assessed whether administration of Dp44mT could relieve clinical symptoms of ovalbumin (OVA)-induced allergic rhinitis (AR) mice. After administration of Dp44mT, number of rubs was significantly decreased, and levels of histamine and IgE were suppressed in serum of AR mice. Also, serum levels of interleukin (IL)-1β, thymic stromal lymphopoietin (TSLP), and tumor necrosis factor (TNF)-α increased by OVA challenge were significantly lowered by administration of Dp44mT. T helper type 1 (Th1) cytokine interferon-γ level was significantly increased by administration of Dp44mT, whereas Th2 cytokines such as IL-4, IL-5, and IL-13 were significantly reduced by administration of Dp44mT. In intranasal tissues of AR mice, levels of IL-1β, TSLP, TNF-α, and IL-6 and activities and protein levels of caspase-1 were significantly reduced by administration of Dp44mT. Interestingly, administration of Dp44mT reduced number of infiltrated eosinophils and mast cells through the inhibition of macrophage inflammatory protein-2 and intercellular adhesion molecule-1 in intranasal tissues of AR mice. In conclusion, these results indicate that Dp44mT also has potential antiinflammatory effects in vivo as well as in vitro.

Therapeutic vaccines for allergic disease

Allergic diseases are highly prevalent worldwide and affect all age groups, contributing to a high personal and socioeconomic burden. Treatment with an “allergy vaccine” or allergen immunotherapy aims to provide long-lasting benefits by inducing unresponsiveness to the relevant antigen. The consequences of the therapy are considered disease modifying and range from dampening of the immediate immune responses to the reduction of secondary tissue remodeling. Furthermore, allergen immunotherapy interventions have a potential to slow or cease the development of additional allergic manifestations with a long-term overall effect on morbidity and quality of life. Here, we review proposed mechanisms underlying the therapeutic effects of immunotherapy for allergic diseases. Further, we discuss both standard and novel approaches and possible future directions in the development of allergen immunotherapy.

Cytokine activation during embryonic development and in hen ovary and vagina during reproductive age and Salmonella infection

Salmonellosis is one of the most important zoonotic diseases and is usually associated with consumption of Salmonella Enteritidis (SE) contaminated poultry meat or eggs. Contamination with SE is usually the result of infection of the digestive tract, or reproductive organs, especially the ovary and vagina. Thus, knowledge of endogenous innate immune mechanisms operating in the ovary and vagina of hen is an emerging aspect of reproductive physiology. Cytokines are key factors for triggering the immune response and inflammation in chicken to Salmonella infection. The aim of this study was to investigate the expression profile of 11 proinflammatory cytokines in the chicken embryos during embryonic development, as well as in the hen ovary and vagina in vivo, to investigate whether sexual maturation affects their ovarian and vaginal mRNA abundance and to determine whether cytokine expression was constitutive or induced in the ovary and vagina as a response to SE infection. RT-PCR analysis revealed that several cytokines were expressed in the chicken embryos, and in the ovary and vagina of healthy birds. Expression of various cytokines during sexual maturation appeared to be developmentally regulated. In addition, a significant up-regulation of several cytokines in the ovary and vagina of sexually mature SE infected birds compared to healthy birds of the same age was observed. These results suggest a cytokine-mediated immune response mechanism against Salmonella infection in the hen reproductive organs.

Intratracheal myriocin enhances allergen-induced Th2 inflammation and airway hyper-responsiveness

Introduction

Ceramide is the central substrate of sphingolipid metabolism and plays a key role in cellular signal transduction pathways, regulating apoptosis, differentiation, and chemotaxis. Alterations in airway ceramide levels are observed in multiple pulmonary diseases and recent human genetic association studies have linked dysregulation of sphingolipid regulatory genes with asthma pathogenesis.

Methods

Utilizing myriocin, a potent inhibitor of sphingolipid synthesis, we evaluated the immune regulatory role of de novo ceramide generation in vitro and in vivo. Intratracheal myriocin was administered alone or during house dust mite sensitization (HDM) of BALB/C mice and airway hyper‐responsiveness (AHR) was evaluated by invasive plethysmography followed by bronchial lavage (BAL) cytology and cytokine quantification.

Results

Myriocin inhibits and HDM exposure activates de novo ceramide synthesis in bone marrow‐derived dendritic cells. Mice receiving intratracheal myriocin developed a mild airway neutrophilic infiltrate without inducing a significant increase in AHR. CXCL1 was elevated in the BAL fluid of myriocin‐treated mice while the neutrophilic chemotactic factors anaphylatoxin C5a, leukotriene B4, and IL‐17 were unaffected. HDM treatment combined with myriocin led to a dramatic enhancement of AHR (63% increase over HDM alone, p < 0.001) and increased granulocyte pulmonary infiltrates versus HDM or myriocin alone. Elevated Th2 T cell counts and Th2 cytokines/chemokines (IL5, IL13, CCL17) were observed in mice treated with combined HDM/myriocin compared to HDM alone. Myriocin‐treated pulmonary CD11c+ cells stimulated with HDM secreted significantly more CXCL1 than cells stimulated with HDM alone while HDM stimulated airway epithelial cells showed no change in CXCL1 secretion following myriocin treatment.

Conclusions

Intratracheal myriocin, likely acting via ceramide synthesis inhibition, enhances allergen‐induced airway inflammation, granulocyte and Th2 lymphocyte recruitment, and allergen‐induced AHR. Sphingolipid pathways may represent novel targets for possible future anti‐inflammatory asthma medications.

Cytokine profiles in nasal fluid of patients with seasonal or persistent allergic rhinitis

Background

New therapeutic approaches with biologic agents such as anti-cytokine antibodies are currently on trial for the treatment of asthma, rhinosinusitis or allergic diseases necessitating patient selection by biomarkers. Allergic rhinitis (AR), affecting about 20 % of the Canadian population, is an inflammatory disease characterised by a disequilibrium of T-lymphocytes and tissue eosinophilia. Aim of the present study was to describe distinct cytokine patterns in nasal secretion between seasonal and perennial AR (SAR/PAR), and healthy controls by comparing cytokines regulating T-cells or stimulating inflammatory cells, and chemokines.

Methods

Nasal secretions of 44 participants suffering from SAR, 45 participants with PAR and 48 healthy controls were gained using the cotton wool method, and analysed for IL-1β, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17, GM-CSF, G-CSF, IFN-γ, MCP-1, MIP-1α, MIP-1β, eotaxin, and RANTES by Bio-Plex Cytokine Assay as well as for ECP and tryptase by UniCAP-FEIA.

Results

Participants with SAR or PAR presented elevated levels of tryptase, ECP, MCP-1, and MIP-1β, while values of GM-CSF, G-CSF, IL-1β, and IL-6 did not differ from the controls. Increased levels of IL-5, eotaxin, MIP-1α, and IL-17 and decreased levels of IFN-γ, IL-12 and IL-10 were found in SAR only. RANTES was elevated in SAR in comparison to PAR. Interestingly, we found reduced levels of IL-4 in PAR and of IL-13 in SAR.

Conclusions

Elevated levels of proinflammatory cytokines were seen in both disease entities. They were, however, more pronounced in SAR, indicating a higher degree of inflammation. This study suggests a downregulation of T_H1 and T_reg-lymphocytes and an upregulation of T_H17 in SAR. Moreover, the results display a prominent role of eosinophils and mast cells in AR. The observed distinct cytokine profiles in nasal secretion may prove useful as a diagnostic tool helping to match patients to antibody therapies.

Altered performance in attention tasks in patients with seasonal allergic rhinitis: seasonal dependency and association with disease characteristics

BACKGROUND

Seasonal allergic rhinitis (SAR) is a chronic disease affecting about 23% of the European population with increasing prevalence rates. Beside classical symptoms (i.e., sneezing, nasal congestion), patients frequently complain about subjective impairments in cognitive functioning during periods of acute allergic inflammation. However, objective evidence for such deficits or the role of potential modulators and underlying mechanisms is limited. The present study aimed to investigate the effect of SAR on attention-related cognitive processes. In addition, relationships between attention performance, sleep and mood disturbances as well as specific disease characteristics as potential modulators of this link were explored.

METHOD

SAR patients (n = 41) and non-allergic healthy controls (n = 42) completed a set of attention tasks during a symptomatic allergy period and during a non-symptomatic period. Influences of sleep, mood, total immunoglobulin E (IgE) levels and individual allergy characteristics on cognitive performance were evaluated.

RESULTS

Compared to healthy controls, SAR patients had a slower processing speed during both symptomatic and non-symptomatic allergy periods. Additionally, they showed a more flexible adjustment in attention control, which may serve as a compensatory strategy. Reduction in processing speed was positively associated with total IgE levels whereas flexible adjustment of attention was linked with anxious mood. No association was found between SAR-related attention deficits and allergy characteristics or sleep.

CONCLUSIONS

SAR represents a state that is crucially linked to impairments in information processing and changes in attentional control adjustments. These cognitive alterations are more likely to be influenced by mood and basal inflammatory processes than sleep impairments or subjective symptom severity.

Allergen-induced accumulation of CD68-,CD123+ dendritic cells in the nasal mucosa

BACKGROUND

Dendritic cells are antigen-presenting cells central to the immune system. They activate and orchestrate the innate and the adaptive immune systems. This phenotypically diverse group can be further divided into 2 subsets, the CD11c+ myeloid dendritic cells (mDCs) and the CD123+ plasmacytoid dendritic cells (pDCs). The aim of the study was to investigate the effect of allergen exposure on dendritic cells in subjects with allergic rhinitis.

METHODS

Atopic and non-atopic subjects were challenged intranasally with birch or timothy allergen. Nasal biopsies were taken before and 24 h after challenge, and were, after CD68 exclusion, stained for expression of CD11c and CD123 to identify dendritic cell subsets. The effect of allergic mediators on CD68⁻,CD123+ cells was studied with flow cytometry analysis in peripheral blood.

RESULTS

The amount of CD68⁻,CD123+ cells increased in the nasal sub-epithelium upon allergen challenge, whereas the number of CD68⁻,CD11c+ cells was unaffected. In vitro study of the effect of inflammatory mediators on pDC phenotype showed an increased activation in response TNF-α, IL-4 and CpG. Furthermore, TNF-α caused a higher activation among atopic than non-atopic subjects.

CONCLUSIONS

An increased number of CD68⁻,CD123+ dendritic cells along with the positive pDC response following stimulation with inflammatory mediators suggest that the increased pDCs may be of an activated phenotype. It also suggests that the inflammatory response by pDCs to mediators such as TNF-α may be markedly higher in atopic subjects. These data support the notion of pDCs as important participants in allergic rhinitis.

The differential evolutionary dynamics of avian cytokine and TLR gene classes

The potential for investigating immune gene diversity has been greatly enhanced by recent advances in sequencing power. In this study, variation at two categories of avian immune genes with differing functional roles, pathogen detection and mediation of immune mechanisms, was examined using high-throughput sequencing. TLRs identify and alert the immune system by detecting molecular motifs that are conserved among pathogenic microorganisms, whereas cytokines act as mediators of resulting inflammation and immunity. Nine genes from each class were resequenced in a panel of domestic chickens and wild jungle fowl (JF). Tests on population-wide genetic variation between the gene classes indicated that allele frequency spectra at each group were distinctive. TLRs showed evidence pointing toward directional selection, whereas cytokines had signals more suggestive of frequency-dependent selection. This difference persisted between the distributions considering only coding sites, suggesting functional relevance. The unique patterns of variation at each gene class may be constrained by their different functional roles in the immune response. TLRs identify a relatively limited number of exogeneous pathogenic-related patterns and would be required to adapt quickly in response to evolving novel microbes encountered in new environmental niches. In contrast, cytokines interact with many molecules in mediating the power of immune mechanisms, and accordingly respond to the selective stimuli of many infectious diseases. Analyses also indicated that a general pattern of high variability has been enhanced by widespread genetic exchange between chicken and red JF, and possibly between chicken and gray JF at TLR1LA and TLR2A.

Intracellular signaling mechanisms regulating the activation of human eosinophils by the novel Th2 cytokine IL-33: implications for allergic inflammation

The novel interleukin (IL)-1 family cytokine IL-33 has been shown to activate T helper 2 (Th2) lymphocytes, mast cells and basophils to produce an array of proinflammatory cytokines, as well as to mediate blood eosinophilia, IgE secretion and hypertrophy of airway epithelium in mice. In the present study, we characterized the activation of human eosinophils by IL-33, and investigated the underlying intracellular signaling mechanisms. IL-33 markedly enhanced eosinophil survival and upregulated cell surface expression of the adhesion molecule intercellular adhesion molecule (ICAM)-1 on eosinophils, but it suppressed that of ICAM-3 and L-selectin. In addition, IL-33 mediates significant release of the proinflammatory cytokine IL-6 and the chemokines CXCL8 and CCL2. We found that IL-33-mediated enhancement of survival, induction of adhesion molecules, and release of cytokines and chemokines were differentially regulated by activation of the nuclear factor (NF)-kappaB, p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways. Furthermore, we compared the above IL-33 activities with two structurally and functionally related cytokines, IL-1beta and IL-18. IL-1beta, but not IL-18, markedly upregulated cell surface expression of ICAM-1. IL-1beta and IL-18 also significantly enhanced eosinophil survival, and induced the release of IL-6 and chemokines CXCL8 and CCL2 via the activation of the NF-kappaB, p38 MAPK and ERK pathways. Synergistic effects on the release of IL-6 were also observed in combined treatment with IL-1beta, IL-18 and IL-33. Taken together, our findings provide insight into IL-33-mediated activation of eosinophils via differential intracellular signaling cascades in the immunopathogenesis of allergic inflammation.

Molecular mechanisms of cytokine and chemokine release from eosinophils activated by IL-17A, IL-17F, and IL-23: implication for Th17 lymphocytes-mediated allergic inflammation

IL-17A and IL-17F are members of the IL-17 family that play crucial roles in allergic inflammation. Recent studies reported that IL-17A and IL-17F production from a distinct Th lymphocyte subset, Th17, was specifically induced by IL-23, which was produced by dendritic cells and macrophages in response to microbial stimuli. The IL-23-IL-17 axis might therefore provide a link between infections and allergic diseases. In the present study, we investigated the effects of IL-17A, IL-17F, and IL-23, alone or in combination, on cytokine and chemokine release from eosinophils and the underlying intracellular mechanisms. Human eosinophils were found to constitutively express receptors for IL-17A, IL-17F, and IL-23 at the protein level. IL-17A, IL-17F, and IL-23 could induce the release of chemokines GRO-alpha/CXCL1, IL-8/CXCL8, and MIP-1beta/CCL4 from eosinophils, while IL-17F and IL-23 could also increase the production of proinflammatory cytokines IL-1beta and IL-6. Synergistic effects were observed in the combined treatment of IL-17F and IL-23 on the release of proinflammatory cytokines, and the effects were dose-dependently enhanced by IL-23, but not IL-17F. Further investigations showed that IL-17A, IL-17F, and IL-23 differentially activated the ERK, p38 MAPK, and NF-kappaB pathways. Moreover, inhibition of these pathways using selective inhibitors could significantly abolish the chemokine release induced by IL-17A, IL-17F, and IL-23 and the synergistic increases on IL-1beta and IL-6 production mediated by combined treatment of IL-17F and IL-23. Taken together, our findings provide insight for the Th17 lymphocyte-mediated activation of eosinophils via differential intracellular signaling cascades in allergic inflammation.

Leptin-mediated cytokine release and migration of eosinophils: Implications for immunopathophysiology of allergic inflammation

Leptin is a pleiotropic adipocyte-derived cytokine used in hypothalamic regulation of body weight and modulation of immune response by stimulating T cells, macrophages and neutrophils. Leptin has been shown to be an eosinophil survival factor. We examined the immunopathological mechanisms for the activation of human eosinophils from healthy volunteers by leptin in allergic inflammation. Adhesion molecules, cytokines and cell migration were assessed by flow cytometry, ELISA and Boyden chamber assay, respectively. Intracellular signaling molecules were investigated by membrane array and Western blot. Leptin could up-regulate cell surface expression of adhesion molecule ICAM-1 and CD18 but suppress ICAM-3 and L-selectin on eosinophils. Leptin could also stimulate the chemokinesis of eosinophils, and induce the release of inflammatory cytokines IL-1beta and IL-6, and chemokines IL-8, growth-related oncogene-alpha and MCP-1. We found that leptin-mediated induction of adhesion molecules, release of cytokines and chemokines, and chemokinesis were differentially regulated by the activation of ERK, p38 MAPK and NF-kappaB. In view of the above results and elevated production of leptin in patients with allergic diseases such as atopic asthma and atopic dermatitis, leptin could play crucial immunopathophysiological roles in allergic inflammation by activation of eosinophils via differential intracellular signaling cascades.

IL-13 blockade reduces lung inflammation after Ascaris suum challenge in cynomolgus monkeys

BACKGROUND

Airway inflammation is a hallmark feature of asthma and a driver of airway hyperresponsiveness. IL-13 is a key inducer of airway inflammation in rodent models of respiratory disease, but a role for IL-13 has not been demonstrated in primates.

OBJECTIVE

We sought to test the efficacy of a neutralizing antibody to human IL-13 in a cynomolgus monkey model of lung inflammation.

METHODS

Using cynomolgus monkeys (Macaca fascicularis) that are sensitized to Ascaris suum through natural exposure, we developed a reproducible model of acute airway inflammation after segmental A suum antigen challenge. This model was used to test the in vivo efficacy of mAb13.2, a mouse mAb directed against human IL-13, and IMA-638, the humanized counterpart of mAb13.2. Bronchoalveolar lavage (BAL) cells and BAL fluid were collected before and after antigen challenge and assayed for cellular content by means of differential count.

RESULTS

Total BAL cell count, eosinophil number, and neutrophil number were all reduced in animals treated with mAb13.2 or IMA-638 compared with values in control animals that were untreated, given saline, or treated with human IgG of irrelevant specificity. In addition, levels of eotaxin and RANTES in BAL fluid were reduced in anti-IL-13-treated animals compared with levels seen in control animals.

CONCLUSION

These findings support a role for IL-13 in maintaining lung inflammation in response to allergen challenge in nonhuman primates.

CLINICAL IMPLICATIONS

IL-13 neutralization with a specific antibody could be a useful therapeutic strategy for asthma.

Predictive factors for late normal tissue complications following radiotherapy for breast cancer

BACKGROUND AND PURPOSE

Radiotherapy after breast-conserving surgery is commonly applied to reduce recurrence of breast cancer but may cause acute and late side effects. To identify prognostic factors for the development of late toxicity after radiotherapy, we conducted a prospective study of breast cancer patients.

PATIENTS AND METHODS

We assessed late complications of radiotherapy and collected information on epidemiologic factors in a cohort of breast cancer patients who had received radiotherapy after breast-conserving surgery. Among 416 patients with complete follow-up data, the association between possible risk factors and development of late complications was evaluated using multivariate logistic regression analysis.

RESULTS

After a median follow-up time of 51 months, 131 (31.4%) patients presented with telangiectasia and 28 (6.7%) patients with fibrosis. We observed a strong association between development of telangiectasia and fibrosis (p < 0.01). Increasing age of the patient was a risk factor for both telangiectasia and fibrosis (p-value for trend <0.01 and 0.03, respectively). Patients with acute skin toxicity (odds ratio (OR) 1.8, 95% confidence interval (CI) 1.0-3.1) were at higher risk to develop telangiectasia. Long-term smoking was associated with a significant increase in risk of telangiectasia compared to non-smokers (OR 2.3, 95% CI 1.2-4.6).

CONCLUSIONS

Our study revealed several factors other than radiation dose that may predispose to late complications following radiotherapy. Further understanding of differences in response to irradiation may advance individualized treatment and improve cosmetic outcome.

Microarray profiling of lymphocytes in internal diseases with an altered immune response: potential and methodology

Recently it has become possible to investigate expression of all human genes with microarray technique. The authors provide arguments to consider peripheral white blood cells and in particular lymphocytes as a model for the investigation of pathophysiology of asthma, RA, and SLE diseases in which inflammation is a major component. Lymphocytes are an alternative to tissue biopsies that are most often difficult to collect systematically. Lymphocytes express more than 75% of the human genome, and, being an important part of the immune system, they play a central role in the pathogenesis of asthma, RA, and SLE. Here we review alterations of gene expression in lymphocytes and methodological aspects of the microarray technique in these diseases. Lymphocytic genes may become activated because of a general nonspecific versus disease-specific mechanism. The authors suppose that in these diseases microarray profiles of gene expression in lymphocytes can be disease specific, rather than inflammation specific. Some potentials and pitfalls of the array technologies are discussed. Optimal clinical designs aimed to identify disease-specific genes are proposed. Lymphocytes can be explored for research, diagnostic, and possible treatment purposes in these diseases, but their precise value should be clarified in future investigation.

Effects of probiotic bacteria in dogs with food responsive diarrhoea treated with an elimination diet*

We evaluated whether a probiotic supplementation in dogs with food responsive diarrhoea (FRD) has beneficial effects on intestinal cytokine patterns and on microbiota. Twenty-one client-owned dogs with FRD were presented for clinically needed duodeno- and colonoscopy and were enrolled in a prospective placebo (PL)-controlled probiotic trial. Intestinal tissue samples and faeces were collected during endoscopy. Intestinal mRNA abundance of interleukin (IL)-5, -10, -12p40 and -13, tumour necrosis factor-alpha, transforming growth factor-beta1 and interferon (IFN)-gamma were analysed and numbers of Lactobacillus spp., Bifidobacterium spp., Enterococcus spp. and Enterobacteriaceae and supplemented probiotic bacteria were determined in faeces. The Canine Inflammatory Bowel Disease Activity Index, a scoring system comprising general attitude, appetite, faecal consistency, defecation frequency, and vomitus, decreased in all dogs (p < 0.0001). Duodenal IL-10 mRNA levels decreased (p = 0.1) and colonic IFN-gamma mRNA levels increased (p = 0.08) after probiotic treatment. Numbers of Enterobacteriaceae decreased in FRD dogs receiving probiotic cocktail (FRD(PC)) and FRD dogs fed PL (FRD(PL)) during treatment (p < 0.05), numbers of Lactobacillus spp. increased in FRD(PC after) when compared with FRD(PC before) (p < 0.1). One strain of PC was detected in five of eight FRD(PC) dogs after probiotic supplementation. In conclusion, all dogs clinically improved after treatment, but cytokine patterns were not associated with the clinical features irrespective of the dietary supplementation.

Interleukin-25–Induced Chemokines and Interleukin-6 Release from Eosinophils Is Mediated by p38 Mitogen-Activated Protein Kinase, c-Jun N-Terminal Kinase, and Nuclear Factor-κB

Interleukin (IL)-25, a novel Th2 cytokine, is capable of amplifying allergic inflammation. We investigated the modulation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases (MAPK) pathways in IL-25-activated eosinophils, the principal effector cells of allergic inflammation, for the in vitro release of chemokines including monocyte chemoattractant protein-1 (MCP-1), IL-8, and macrophage inflammatory protein (MIP)-1alpha, and inflammatory cytokine IL-6. Gene expression of chemokines and IL-6 was evaluated by RT-PCR, and concentrations of chemokines and cytokine were measured by cytokine protein array, cytometric bead array, and enzyme-linked immunosorbent assay. NF-kappaB, c-Jun amino-terminal kinase (JNK), and p38 MAPK activities in eosinophils were assessed by electrophoretic mobility shift assay and Western blot. IL-25 was found to upregulate the gene expression of chemokines MCP-1, MIP-1alpha, and IL-8, and cytokine IL-6, in eosinophils, and to significantly increase the release of the above chemokines and IL-6 from eosinophils. IL-25 could also activate the JNK, p38 MAPK, and NF-kappaB activities of eosinophils, while inhibitor of IkappaB-alpha phosphorylation (BAY11-7082), JNK (SP600125), and p38 MAPK (SB203580) could suppress the release of IL-8, MIP-1alpha, MCP-1, and IL-6. Together, the above results showed that the induction of MCP-1, MIP-1alpha, IL-8, and IL-6 in IL-25-activated eosinophils are regulated by JNK, p38 MAPK, and NF-kappaB pathways.